Vapor discharge device



Filed Feb. 26, 1931 m ou 2 0 kix His Attorney Patented Oct. 8, 1 935UNITED STATES PATENT OFFICE VAPOR DISCHARGE DEVICE York ApplicationFebruary 26, 1931, Serial No. 518,589 In Germany March 7, 1930 1 Claim.

This invention relates to vapor discharge devices, more particularly tomercury vapor devices such as rectifiers or inverters which include anevacuated metal-walled container, and

5 has for its principal object the provision of means for preventingshort-circuits between the cathode and container through the mercuryflowing back to the cathode from the condensing surfaces within thecontainer.

In metal vapor discharge apparatus, for eX- ample mercury vaporrectifiers, comprising a receptacle or container wall of metal and inwhich the mercury which has been vaporized and thereafter condensedflows back in the liquid state to an electrode, usually a cathode,short-circuits often occur between the metal tank or container and thiselectrode through the stream of metal condensate which is flowing back.

In accordance with my invention this difficulty is overcome by reducingthe streams of condensate to the form of drops before the returningmetal reaches the electrode. This result is accomplished by causing themetal which is flowing back from the usual condensate receptacle,channel or trough at the bottom of the tank to flow from the troughthrough conduits or pipes only, provided with small nozzles or openings,and to issue from these openings in thin jets which separate into dropsbefore reaching the electrode surface. The arrangement of the conduitsand apertures is advantageously such that the fine jets of mercury fallto the cathode in a long are, the mercury thereby being separated intodrops before reaching the cathode, or the jets on issuing from theconduit nozzles may be arranged to strike a surface or member which isat a potential different from that of the cathode or which consistsofinsulating material. On this surface thejets split up into smalldrops.

The breaking up of the jet into small drops is attained, however, onlyif the jet of liquid metal is sufficiently fine and moves at highvelocity. Therefore, the conduit or outflow pipe is made of such lengthand the jet openings therein so nar row that a velocity head ofapproximately 2 to 3 cm. height of the mercury is attained at theoutflow.

In order to prevent the returning-mercury from passing directly into theactive portion of the cathode it is further of advantage to divide thecathode surface into two parts by means of a quartz cylinder which isotherwise also usually employed by reason of temperature considerations.If then the condensate is arranged to flow to the outer annular surfaceof the cathode the impurities which flow back with the condensate,assuming these impurities are not alloyed with the mercury, will beseparated from the condensate since the impurities float on the surfaceof the mercury. The returning mercury or condensate itself, however, isconducted back in a usual manner, through an opening in the quartzcylinder below the surface of the mercury, into that portion of thecathode which comprises the inner circular surface thereof.

My invention will be better understood from the following descriptionwhen considered in connection with the accompanying drawing and itsscope will be pointed out in the appended claim.

Referring to the drawing, the single figure thereof illustratives avapor discharge device embodying the invention.

In the figure the vapor discharge device I comprises a metal-walledcontainer or tank 2 at the bottom of which is mounted a cathode vessel 3insulated from the container 2 by insulator 4 and containing the liquidmetal or mercury cathode '5. Mercury vaporized by the are dischargeduring operation of the device and rising from the cathode 'isthereafter condensed on cooling surfaces 6 and flows therefrom through apipe l back into the lower portion of the tank to a condensatecollecting basin or receptacle 8 formed by a raised edge or flange 9connected to the container wall.

From the collecting receptacle 8 the condensate is arranged to drain offonly through a plurality of conduits such as tubes it only one of whichis shown in the drawing. These tubes are closed at the bottom andprovided with small openings or nozzles l I, through which thecondensate flows out in the form of thin jets or streams which break upinto drops before reaching the surface of the mercury cathode, or whichstrike the surface of a member l2 which is insulated from the cathode ormay be formed of insulating material, the jets being finely divided intodrops on the surface of this member. The cathode is preferably dividedinto the annular portion I3 and the central portion M by the quartzcylinder l5, and the returning mercury flows to the annular portion andthence to the central active portion I4, any impurities not alloyed withthe mercury floating on the surface of the annular portion and thusbeing kept away from the surface of the active portion.

Since the streams of the returning mercury condensate are caused to bediscontinuous in all or a part of that portion of their path which isbetween the lower end of the conduits l0 and the surface of the mercurycathode, the condensate traversing all or a part of this portion of itspath in the form of drops, short-circuits between the cathode and partsof the device insulated therefrom, due to current flowing through thereturning mercury condensate, are prevented.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

In a vapor discharge device comprising an evacuated metallic receptacle,a mercury cathode insulated from said receptacle, means including acylindrical member of insulating material immersed' in said mercurycathode and projecting upwardly a substantial distance from the surfaceof said cathode to separate said mercury cathode into a central activeportion and an annular portion surrounding said central active portion,

means to condense vapor rising from the cathode, and a condensatecollecting receptacle arranged above said annular portion of thecathode, a plurality of condensate discharge conduits mounted outsidesaid cylindrical insulating member and depending from said condensatecollecting receptacle, each of said conduits having a small openingadjacent the bottom thereof to cause said condensate to flow from saidconduits under pressure in the form of a plurality of fine jets, andmeans including a member in-

